<div>Background: Energy is the major nutrient needed for dairy cattle and its insufficient intake has a detrimental effect on their reproductive activity.&nbsp; 
 
Methods: The aim of this study was to investigate the effect of biostimulation on behaviour and energy balance of Sahiwal cows during peri-estrus through 2 types of bull contact. For this, 24 postpartum cows were divided into 3 similar groups (T0, T1 and T2) of 8 cows each. In T0, cows were not exposed to bull; in T1 the cows were exposed to bull through a fence-line contact and in T2, the cows were in direct bull contact for 12 hours daily.&nbsp; 
 
Result: In first post-partum estrus, the feeding time was non-significant among 3 groups but in second estrus, mean time spent on feeding was significantly (p&lt;0.05) lower in T0 than T1 and T2 groups. The mean rumination time on d-0 of first estrus was significantly (p&lt;0.01) lower in T1 and T2 cows as compared to T0 cows. Mean rumination time on d-0 in second estrus was significantly (p&lt;0.05) lower in T1 and T2 than in T0. Mean resting times in first estrus in T1 and T2 were significantly lower (p&lt;0.05) than in T0. Mean resting time in d-0 of second estrus was significantly (p&lt;0.05) lower in T1 and T2 than the T0. There was no significant difference in the mean dry matter intake and levels of BHBA and NEFA among 3 groups of cows. It was concluded that biostimulation of Sahiwal cows through direct or fence-line bull contact during peri-estrus period highly reduced their feeding, rumination and resting times without affecting their energy balance as compared to non-bull exposed cows.</div>

<div>Effect of Biostimulation on Some Behavioral Aspects and Energy Balance of Sahiwal Cows during Peri-estrual Period</div>

In order to study the plasma hormonal and metabolic changes in Zebu (Sahiwal) cattle during summer and winter season, five each of periparturient high and low yielding cows were selected from Livestock Research Centre, ICAR-NDRI, Karnal. Blood samples were collected on days -45, -30, -15 (prior to parturition), 0 (day of parturition) and 15, 30, 45 (postpartum) during both the seasons and plasma was separated. Plasma cortisol levels were significantly higher on day of parturition and during postpartum period in both the groups during both the seasons. Plasma insulin levels were significantly (P&lt;0.05) lower during summer in high yielder group. On the day of calving, plasma T3 and T4 levels were significantly (P&lt;0.05) lower in high yielders during both seasons. Plasma leptin levels were lower (P&lt;0.05) on day of parturition in high yielders than low yielders during both seasons. Plasma glucose levels were significantly lower (P&lt;0.05) on day of parturition and remained low during postpartum period in both groups during both seasons comparel to prepartum period. Plasma NEFA levels of both groups of cows were higher on the day of calving and remained higher during postpartum period over pre calving values. High yielder cows showed more deviation in stress markers viz. cortisol and NEFA than low yielder cows. Therefore, special attention should be given to feeding and management of the lactating animals (especially high yielding cows during summer) around parturition for sustained productivity and maintenance of homeostasis. 
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Plasma profile of hormones and energy metabolites in low and high producing periparturient Sahiwal cows during summer and winter season

<div>Background: Milk production is one of the most important economic traits in dairy cattle. Crossing of zebu cattle (Bos indicus) with temperate cattle breeds (Bos taurus) was undertaken to improve the milk production in India. Crossbreeding has resulted in improved production performance of the dairy animlas over the past few decades. 
 
Methods: Data on 50 purebred Sahiwal cows from the Livestock Farm Complex, College of Veterinary Science, Rajendranagar, Hyderabad and 50 Holstein Friesian &times; Sahiwal crossbred cows maintained at the Military Dairy Farm, Secunderabad were utilized to study the influence of breed and parity on various production and reproduction traits. The various traits studied were: Total lactation milk yield (TLMY) Lactation length (LL), Peak yield (PY), Age at first service (AFS), Age at first calving (AFC), Gestation period (GP), Service period (SP), Dry period (DP) and Calving interval (Cl). 
 
Result: In the present study, significant effect of breed was found on the TLMY and PY with the crossbreds recording higher values for both the traits. The means for TLMY, PY, LL, GP, SP, DP and CI were 1768.32&plusmn;109.67 kg, 10.17&plusmn;0.50 kg, 304.41&plusmn;13.00 days, 277.71&plusmn;2.24 days, 182.60&plusmn;15.51 days, 167.47&plusmn;10.68 days and 430.23&plusmn;13.46 days in Sahiwal and 2983.45&plusmn;78.32 kg, 14.92&plusmn;0.36 kg, 324.71&plusmn;9.29 days, 275.34 days, 181.09&plusmn;10.91 days, 127.01&plusmn;7.51, 413.61&plusmn;9.47 days in crossbred cows respectively. It may be concluded that the productive performance of crossbred cows was better than that of indigenous cows.</div>

Production and Reproduction Performance of Sahiwal and HF &times; Sahiwal Cows

The study was undertaken to determine the composition of colostrum and milk of Hill cattle during postpartum period and compared them to Sahiwal and crossbred cow. Fifteen colostrum samples per day from each group of cow (as per availability) were collected during first five postpartum days while as milk samples were collected from eight cow each of Sahiwal and crossbreds and six form Hill cow, at fortnightly interval up to 32 weeks postpartum. These samples were subjected to various physico-chemical analyses. There was a significant (P0.05) difference between overall mean protein per cent, pH and electrical conductivity in the colostrum of Hill cow, Sahiwal and crossbred cow but lactose per cent did not diffe significantly. In milk there was a significant (P0.05) difference between overall mean of fat, protein, solid not fat, total solids per cent, pH, electric conductivity, somatic cell count and milk yield of Hill cow, Sahiwal and crossbreds while non-significant (P0.05) difference was noticed for lactose per cent and specific gravity. The colostrum of Hill cow and Sahiwal were richer in protein, fat, lactose, TS and ash content as compared to crossbred cow. Milk of Hill cow had higher content of protein, fat, SNF, TS and lower pH, EC and SCC compared to crossbreds and Sahiwal.

Colostrum and milk composition during postpartum period in Hill cow, sahiwal and crossbreds cow

<div>Background: Growing demand for improving milk production and rising temperatures due to global warming has increased the thermal load on dairy animals. Physiological parameters such as respiration rate and body temperature mainly determine the adaptability of animals to climate stress. During genetic adaptation, Bos indicus cattle have acquired thermo tolerant genes and when exposed to heat stress conditions, the Bos indicus cattle have lower respiration rates and rectal temperatures than Bos taurus animals. The present study was aimed to study the effect of seasons on the physiological responses in Sahiwal and crossbred cows. 
 
Methods: A total of 50 crossbred cows maintained at Military dairy Farm, Secunderabad and 50 Sahiwal cows maintained at Livestock Farm Complex, College of Veterinary Science, Rajendranagar, PVNRTVU were utilized for the present investigation. The study was conducted during summer (THI = 83.71&plusmn;0.01), rainy (THI = 71.37&plusmn;0.01) and winter (THI = 66.69&plusmn;0.01) seasons. Changes in respiration rate (RR), rectal temperature (RT) and heat tolerance coefficient (HTC) were observed in different seasons in Sahiwal and crossbred cows. 
 
Result: RR (breaths/ min) in Sahiwal cows during summer, rainy and winter were 28.56&plusmn;0.38, 23.38&plusmn;0.38 and 20.54&plusmn;0.38 respectively whereas RR (breaths/ min) in crossbred cows were 44.58&plusmn;0.38, 25.94&plusmn;0.38 and 21.90&plusmn;0.38 respectively. In Sahiwal cows RT (&deg;C) during summer, rainy and winter were 38.52&plusmn;0.03, 38.23&plusmn;0.03 and 38.13&plusmn;0.03 respectively whereas RT (&deg;C) in crossbred cows were 39.22&plusmn;0.02, 38.72&plusmn;0.03 and 37.80&plusmn;0.03 respectively. The magnitude of increase in RR, RT and HTC were found to be higher during summer compared to other seasons in both Sahiwal and crossbred cows. It was observed that Sahiwal cows are less sensitive to heat stress and are better able to regulate their body temperature than crossbred cows when environmental temperature increases during summer. The HTC values were lower in Sahiwal cows in all the seasons studied indicating better thermo tolerance when compared to the crossbred cows.</div>

Effect of Seasons on Physiological Responses in Sahiwal and Crossbred Cows

<div>Background: Beta-carotene (BETA) is a precursor of retinol (Vitamin A) and positively influenced on reproductive efficiency in cows. The aim of the study was to determine the effect of orally supplementation of beta-carotene on plasma carotene content and fertility rate of lactating crossbred Sahiwal cows. 
 
Methods: Twenty-four disease-free lactating crossbred Sahiwal cows with a close date of calving were randomly divided into two homogeneous groups for Control group (CONT; n = 12) and Beta-carotene group: 500 mg/cow/d (BETA; n = 12) from 7 days post partum (dpp) until 105 dpp thereafter on concentrations of beta-carotene and selected protein and energy parameters in plasma were determined. In addition, effects on fertility rate were studied. 
 
Result: Beta-carotene concentrations increased in plasma of beta-carotene (BETA-group) supplemented cows compared to control (CONT-group) cows (p&lt;0.001). In BETA-group cows, urea concentration in blood plasma decreased significantly compared to cows of CONT-group (p&lt;0.001) but did not differ in total protein, albumin, glucose and total cholesterol content in cows of both groups. Occurrence of first post partum estrus decreased (p&lt;0.001) in beta-carotene (BETA-group: 74 dpp) cows compared to control (CONT-group: 81 dpp) cows. In this study, it was observed that the overall conception rate was higher (p&gt;0.001) in BETA-group: 83.33% (cows pregnant: 10/12) and lesser in the CONT-group: 50.00% (cows pregnant: 6/12). The results of this study indicated that oral supplementation with beta-carotene increased the concentration of beta-carotene and decreased the concentration of urea in plasma and cows with higher blood plasma beta-carotene content improved fertility over cows with lower blood plasma beta-carotene content.</div>

​Effect of Beta-carotene Supplementation on Plasma Carotene Content and Fertility of Lactating Crossbred Sahiwal Cows

<div>Negative energy balance condition during transition period is a gateway for production and infectious diseases during periparturient period. Energy balance is calculated directly through difference in energy input and energy output or indirect methods like estimation of energy metabolites (NEFA, BHBA and glucose level), Body condition scoring (BCS), back fat thickness, body weight and milk components (e.g., fat protein ratio), etc., at herd level. All the indirect energy balance indicators were studied in relation to postpartum health and performances in dairy animals. Blood biochemical parameters are routinely used for evaluation of general health status of animals. But, their relationship with energy balance in early lactating cows is not clear. In this review, effects of energy balance, critical period to assess the energy balance, and blood biochemical parameters in relation to energy balance, milk yield and health status of dairy animals are discussed. We also discussed energy balance indicators in other biological fluids in dairy cattle.</div>

Biochemical Indicators of Energy Balance in Blood and Other Secretions of Dairy Cattle: A Review

A field study on early lactating crossbred cows (n=35) was conducted to evaluate the effect of feeding balanced rations on milk production, enteric methane emission, metabolites and feed conversion efficiency (FCE). In comparison to requirements, the dietary intake of protein and energy were higher by 25.0 and 12.7% whereas, calcium and phosphorus intake were lower by 30.0 and 27.0%, respectively. Balanced feeding improved daily 4% FCM yield by 0.7 kg/cow (P&lt;0.05) and intestinal flow of microbial nitrogen (N) by 37.0% (P&lt;0.01), whereas, reduced (P&lt;0.01) feeding cost by 17.0% and enteric methane emission (g/d/cow and g/kg milk yield) by 14.6 and 18.1%, respectively. Level of IgG, IgA, IgM and uric acid content increased significantly, whereas BUN level reduced (P&lt;0.01) from 18.2 to 15.0 mg/dl. FCE improved (P&lt;0.01) from 0.8 to 1.0 and efficiency of microbial protein synthesis also improved (P&lt;0.01) by 63.6% owing to feeding of balanced rations indicating better performance of cows. Present study indicates that feeding nutritionally balanced rations improved milk production, feed conversion efficiency and reduced methane emission in lactating cows under field conditions.

Impact of feeding balanced rations on milk production, methane emission, metabolites and feed conversion efficiency in lactating cows

Background: Bovine lameness predominantly due to foot disorders is a severe herd health concern instigating substantial influence on dairy economics owing to increased odds of mastitis and reduced fertility. Timely diagnosis and treatment of lameness can save these economic losses. The current study was aimed to evaluate lameness and its effect on animal health in terms of body condition score and on udder health in Sahiwal cows. 
 
Methods: 204 lactating Sahiwal dairy cows in different lactation lengths and parities, from local Sahiwal farms in Punjab were evaluated for lameness. Cows were scored for body condition and lameness. Quarter foremilk used to determine the quarter health status of the cows by California mastitis test (CMT) and bacteriological culture and cow composite milk samples for estimation of somatic cell count (SCC), electrical conductivity, pH and milk composition, in terms of fat, solids not fat, protein and lactose were collected maintaining aseptic conditions. 
 
Result: 34 per cent had asymmetry in gait or mild lame, 5 per cent had moderate lameness and 1 per cent had severe lameness. Lameness had no significant effect on the body condition scores of Sahiwal cows. Subclinical mastitis was found in 40.2 per cent of Sahiwal dairy cows. It was concluded that incidence of mastitis was higher in the lame group as revealed by CMT and bacteriological culture and the lame group had significantly (P&lt;0.05) more SCC and electrical conductivity than healthy cows. However, milk composition was not affected by lameness.

Association of Lameness with Body Condition Score, Udder Health and Milk Quality in Sahiwal Dairy Cows

Background: Cellular tolerance to heat stress is mediated by heat shock proteins (HSPs). The HSPs act as molecular chaperones and are transcribed in response to stress. Among different families of these proteins, HSP70 is considered to be related to the development of temperature tolerance. Unraveling polymorphism in heat shock protein genes could be a step towards the identification of genetic markers for selecting heat-tolerant cattle.&nbsp; 
 
Methods: The present study was carried out in Sahiwal (n=50) and Crossbred cows (n=50) with the objective to identify polymorphisms in HSP70 gene. Two fragments (295 and 220 bp) of HSP70 gene were subjected to Polymerase Chain Reaction-Single-Strand Conformation Polymorphism (PCR-SSCP) technique. Statistical analysis was performed to study the association of each SSCP genotype on physiological, production and reproduction traits in Sahiwal and crossbred cows using the univariate GLM model of SPSS 25. 
 
Result: The PCR-SSCP of 295 bp fragment of HSP70 gene revealed two genotypes AA and AB in Sahiwal cows and two genotypes AA and AC in crossbred cows. The association analysis revealed that genotype AA had higher peak milk yield in Sahiwal cows while the same genotype had higher total lactation milk yield, lower service period and calving interval in crossbred cows. The 220 bp fragment was found to be monomorphic in both Sahiwal and crossbred cows.&nbsp;

Association of SSCP Polymorphisms of HSP70 Gene with Physiological, Production and Reproduction Performance in Sahiwal and Crossbred Cows